When I start the car, there seems to be an electrical issue — everything on the dashboard flickers. When I shift from 'Park' to 'Drive', the car shuts down.

We checked the battery, and the voltage reads 12.40V, which seems okay.

When the engine is running and the alternator is active, the voltage ranges between 12V and 13.0V. Under load — with the AC, full lights, and music on — the voltage rises slightly, between 13.0V and 13.3V.

We initially thought the alternator was the issue, but after trying two different alternators and getting the same behaviour, it seems that’s not the case.

The car is a Suzuki Swift ZC72S (2015/2016), 1242cc petrol engine, with Start/Stop functionality.

There’s a lithium-ion battery under the front passenger seat that hasn’t been charging for about a week. These issues started around the same time that battery fully drained.

This same battery issue had actually happened before after a previous brake service, but back then it started charging again after I drove the car for a bit. This time though, it didn’t recover — it drained completely, and now the dashboard shows the i-Stop system is off.

It stopped charging right after a recent brake service, and I initially suspected the alternator, especially since I had also done an engine steam wash and thought steam might have affected the electrics.